Pulmonary imaging techniques have traditionally emphasized the description of the anatomy and pathology of the lung parenchyma, airways, and vasculature. Recent developments in functional lung imaging and, in particular, hyperpolarized (HP) 3He MRI have generated interest for their ability to improve upon the results attained by these traditional techniques. The goal of this proposal is to implement the novel HP 3He MRI technique to generate physiological maps of regional parameters that describe lung function. The central hypothesis of this proposal is that HP 3He MRI maps of regional physiological parameters that describe lung function (i.e., regional ventilation, regional perfusion, perfusion efficiency index, regional alveolar partial pressure of oxygen, regional VA/Q) will more accurately detect early functional and structural changes in a diseased lung than existing imaging modalities. We will test our hypothesis by establishing the following specific aims: 1) To measure regional ventilation in healthy Yorkshire pigs and in pigs with increasing ventilation abnormality, 2) To measure the regional lung partial pressure of oxygen in healthy Yorkshire pigs and in pigs with varying regional ventilation and/or perfusion abnormality, 3) To measure the regional perfusion and the regional perfusion efficiency index in healthy Yorkshire pigs and in pigs that have been administered vasoconstrictor therapy, and 4) To obtain the regional VA/Q in healthy Yorkshire pigs and in pigs with increasing ventilation and perfusion abnormalities. This work will contribute towards the pivotal implementation of specific markers for the detection of and therapy for many pulmonary disorders. Our technique will delineate with greater accuracy the structural and functional changes associated with pulmonary diseases.